Cancer is a significant problem in human health all over the world. At present, there are a number of methods and techniques for the treatment of cancer. A safe and effective cancer treatment has been the goal of investigators for a substantial period time. A technique for the successful cancer treatment must ultimately differentiate cancer cells from normal cells and must selectively weaken or kill only the cancer cells without affecting the normal cells. Some cancers such as eye cancer and liver cancer cannot be completely treated by a surgical operation.
Chemical therapy, radiate therapy and surgical operation are developed for the treatment of cancer.
In chemical therapy, a chemical material is administered to a body, which kills the cancer cell.
In surgical operation, the affected part of cancer is removed or dressed.
In radiate therapy, the radioactive element which radiates β(beta)-ray is used for treatment of cancer. The radiate therapy is divided into outer and inner radiate therapys. Outer radiate therapy is to kill the cancer cells by the β-ray radiated from outside. However, the disadvantage of outer radiate therapy is that the treatment efficiency is low and the side effect is too large because the radiation kills the cancer cell during treatment and at the same time destroys a lot of normal cells as well. Inner radiate therapy is to inject radioactive magnetic fluids into the body, and to kill the cancer cell by the β-ray radiated from the radioactive magnetic fluids under external magnetic field.
Particularly, in the inner radiate therapy, magnetic nanoparticles prepared with elements emitting the β-ray are coated with the surfactants to form the magnetic fluids which are injected into the body. Under external magnetic field, the β-ray radiated from the magnetic fluids is positioned around the affected part to kill the tumor cells.
The magnetic fluids used in inner radiate therapy is magnetic colloidal liquid prepared by the steps: 1) coating the magnetic powder with various surfactants, in which the magnetic powder is magnetic oxides such as MO·Fe2O3 (M: metal cation of 2+) with a mean size of 100 Å; and 2) dispersing homogeneously and stably the said coated particles into a liquid.
The magnetic fluids as colloidal particles in a suspension are not agglomerated or precipitated by gravity or magnetic force.
U.S. Pat. No. 5,921,244 suggests the process of magnetic fluids containing the particles coated with photoreactive agent. However, it is restricted within the purpose of drug therapy by a light source using a magnet inserted into the body. Also, U.S. Pat. No. 4,957,481 deals with the effective amount and direct injection of a photosensitive compound into tumor, and the application and activation of light source.